(1) Nothing in this chapter shall affect any existing water rights including, among others, riparian, appropriative, and federal Indian and non-Indian reserved rights, existing on the effective date of this chapter, nor shall it affect existing rights relating to the operation of any navigation, hydroelectric, or water storage reservoir or related facilities.

(2) Single domestic use and stockwatering use shall be exempt from the provisions established in this chapter except that, when the cumulative impacts of numerous domestic diversions begins to significantly affect the quantity of water available for instream uses or the maintenance of lake levels, then any water rights issued after that time shall be issued only for in-house use if no alternative supply is available.

(3) Nonconsumptive uses which are compatible with the intent of the chapter may be approved.